Circuit interrupter



Aug. 16, 1949.

L. R LUDWlG ETAL CIRCUIT INTERRUPTER Filed May 19, 1945 WITNESSES: (Z4

INVENTORS lean B ludwl'y'an'd Beqgmin Paola er.

Patented Aug. 16, 1949 Leon R. Ludwig Wilkinsburg,

and Benjamin 2.

Baker, Turtle Creek, Pa., assignors to Westinp house Electric Corporation, East Pittsburgh,

Pa., a corporation of Pennsylvania Application May 19, 1945, Serial'No-c594;634 Claims. (Cl. 2 U0-'14 4) This invention relates to circuit interrupters in general, and more particularly to are extinguishing structures and mounting arrangements therefor.

In U. S. patent application filed April 30, 1945, Serial No. 591,047, by Leon R. Ludwig and Benjamin P. Baker and assigned to the assignee of the instant application, there is shown and described a circuit interrupter of improved mounting construction embodying a supporting means disposed at groundtpotential which supports a high voltage termi al bushing intermediate the ends thereof. It is an object of our invention to further improve the mounting construction: disclosed and claimed in this application.

Amore specific object-isto provide an'improved circuit interrupter having improved mounting constructional features in which conducting means are supported by support means and have an arc extinguishing unit secured to one end thereof. Preferably, terminal-means are asso ciated with the are extinguishing unit and are positioned closely adjacent thereto.

[mother object is to provide an improved aircuit interrupter of the type comprising a single terminal bushing supported bysupport means and having an arc extinguishin unit'secured to one end thereof. Preferably, movable contact means are actuated toward'andiaway from the-same end of the bushing. and ar actuated by operating means at lea-st in part'supportedby the supporting means.

Further objects and advantageswillreadily be come apparent upon. aireading of the following.

specification taken in conjunction with the*draw-' ing in which: i

Figure 1 is a sideelevational view of a circuit interrupter embodyingourinvention;

Fig. 2 is an elevational view' partially in section of the interrupter shown in Fig. 1 with the supporting frameworkomitted and the view enlarged to-more clearly show the enclosure therefor, the contacts being shown in the fully open circuit position of the interrupter; and

Fig. 3 is a view similar to Fig. 2 but showing amodified type of arc'extinguishing unit and in which the-contacts are shown in the closed circuit position.

Referringto'the drawing; and more particularly to'Fig. 1 thereof,-the referencenumeral l gener-- ally designates supportingmeans disposed :at ground potential and comprising- .a plurality of vertically extending channel-members- '2 bracedbydiagonally extending-support. The support in means I is supportedon a base The sup-" ,2 porting means I- rigidly supports in place a circuit interrupter 5 having .an upper line terminal 6 and a lower line terminal 1. The conductors 8, 9 connect the circuit interrupter 5 into the electrical circuit tobe protected.

Fig. 2, which shows more clearly the internal construction of the interrupter 5,- shows an arc extinguishing unit HI- threadedly secured and clamped into-place at- H to the lower end of the high voltage bushing 1-2, the latter being supported by the supporting means. Conducting means l3 forthe-interrupter extend through the high voltage bushing l-2 andserve to carry the electrical circuitthrough the supporting means I totheupper line-terminal 6 of the interrupter.

The are extinguishing-unit lll-v forms no part of our invention and-inthisinstanceis shown as being of the typein which a pressure-generating break is establis-l'ledprior tothe formation of an interruptingbreak. The contact structure for the arcextinguishin'g unit lo'comprises a stationary pressureagenerating. contact 14 which is cooperablewith anci-ntermediate contact! 5, the latter being spring-biased downwardly by a compressionspring Hand-cooperating with amovable contact H to establish an interrupting arc. Oil under pressure created at-the pressure-generating break is. forced'tofiow by suitable passage means into the interruptingbreak to'consequently effect the extinction of theinterrupting are drawn betweentheintermediateucontact l5 and the lower movable contact I L Theipassagearrangement is preferably of the type set forth in U. S. patent application, filed November 11, 1942, Serial No. 465 244, now U. S. Patent:2;406-,469, issued August 27-, 1-946, by Leon R.- Ludwig, Winthrop M. Leeds and Benjamin" P. Baker and assigned to the assignee of the instantapplication. However, the passage arrangement asset forth in the aforesaid patent could be varied imany desired'manner, the particular are extinguishing unit part of our. inventiomaswillmore fully be apparent hereinafter.

Surrounding the arc-extinguishing-unit Illand the lower iendrof the high voltage terminal bushing 12 1s an insulatfng 'cylinder la, in turn surrounded by aucylinder 19,: the latter being composed of porcelain orother suitable weatherproof materlaL The lower'endsof the porcelaincasing l9 rests upona terminal housing 20 in which are disposed-a plurality'of'spring washers 2L The springwashersrlt cooperate wlth boltsfl tomaintain the porcelain: casing Hl-in compression and to maintain the insulating cylinder l8 inten-' l0 forming no The terminal housing 20 also supports a contact guide 23 with contact bearing portions 23a to guide the reciprocating longitudinal movement of the lower movable contact H, the latter being actuated by an insulating operating rod 24 making pivotal engagement thereto at 25. The upper end of the operating rod 24 makes pivotal engagement at 26 to a crank lever 21, the latter being rotated by an operating shaft 28.

From the foregoing, it will be apparent that rotation of the shaft 28 will cause rotation of the crank and longitudinal movement of the operating rod 24, which extends substantially longitudinally of the terminal bushing l2. To effect closure of the contact structure, it is necessary to rotate the shaft 28 in a clockwise direction. This effects upward movement of the operating rod 2d and correspondingly upwardmovement of the movable contact H, which after picking up the intermediate contact i5, causes engagement between the stationary contact l4 and the intermediate contact 15. Thus, the electrical circuit through the interrupter extends downwardly through the high voltage terminal bushing I2, through the stationary contact l4, intermediate contact 15, movable contact ll, through contact bearing portions 23a associated with the contact guide 23, metallic cap 23b, casting 230 to the lower terminal I of the interrupter.

In the interrupter shown in Fig. 3, the construction is generally similar to the construction hereinbefore described in connection with Fig. 2. However, a hook-shaped movable contact member 30 pivotally mounted at 3| to a bracket 32 is actuated by the operating rod 24 and. makes engagement with stationary contact structure 33. The lower terminal 29 of the interrupter is electrically connected to the bracket 32. The are extinguishing unit 34 is of modified construction,

the details of which are fully shown and claimed in U. S. Patent 2,039,054, which issued April 28, 1936, to Samuel H. Boden and Stanley T. Schofield and which is assigned to the assignee of the instant application.

Preferably, the arc extinguishing action which takes place in the operation of such an are extinguishing unit causes the single are drawn between the contacts 30, 33 to be moved toward the left, as viewed in Fig. 3, into suitable constrictions and permits it to intimately engage fresh oil which fills the cylinder [8. The plate structure is completely set forth in the aforesaid pat-- ent; consequently, since the arc extinguishing unit 34 specifically forms no part of our invention, merely a brief description of the are extinguishing action is thought necessary. Following the leftward movement of the are into the pockets and constrictions afforded by the plate structure as caused by U -shaped plates formed of magnetic material, rapid arc extinction soon takes place. Continued downward movement of the movable contact 30, as caused by downward movement of the insulating rod 24, effects an isolating gap into the circuit.

From the foregoing description, it will be apparent that we have provided an improved circuit interrupter of the single bushing type in which only a single arc extinguishing unit is necessary, and in which the isolating gap in the interrupter is caused by continuedmovement of the movable contact. The simplicity of the construction lends itself readily to economic manufacture. Since the arc extinguishing units ii], 34 are rigidly secured to the lower ends of the high voltage terminal bushings 12, there is hence pro- '4 vided rigid support for the several parts of the interrupter. By causing the operation of the interrupter to be effected by rotation of the shaft 28, the arrangement is particularly suitable for two or more interrupters 5 controlling the several phases of a transmission line.

The entire breaker may be mounted with the bushing terminal end up or down. It is, thus, possible to have the interrupter above or below the interrupting oil gap for either position of the breaker mounting.

Current transformers 35, surrounding the terminal bushing l2, are supported by the framework I and are preferably used to initiate relay operation to effect opening of the interrupter during the existence of overload conditions in thecircuit controlled by the interrupter. The general. breaker arrangement not only results in a much cheaper breaker and one which can be serviced more easily but permits of greater switch yard flexibility. Also features of the construction are readily applicable to circuit interrupters of the compressed air type or even of the airbreak type. Merely for purposes of illustration have we illustrated a preferred embodiment of our invention as one of the liquid-break type.

Although we have shown and described specific structures, it is to be clearly understood that the same were merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. In a circuit interrupter, supporting means at ground potential, a casing secured to said grounded supporting means and having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing extending through and being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing projecting into one end of the casing and having the interior end thereof terminating adjacent the mid-portion of the casing, an arc extinguishing unit secured to the interior end of the terminal bushing, line terminal means for the interrupter disposed adjacent the other' end of the casing, movable contact structure disposed within the casing and separable to establish an are within the are extinguishing unit, and actuating means for the movable contact structure carried by the grounded supporting means.

2. In a circuit interrupter, supporting means at ground potential, a casing having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing projecting into one end of the casing, and having the interior end thereof terminating adjacent the mid-portion of the casing, an arc extinguishing unit secured to the interior end of the terminal bushing, line terminal means for the interrupter disposed adjacent the other end of the casin movable contact structureincluding a movable contact disposed within the casing and separable to establish an-arc 'withlnthe arc extinguishing unit, rotatable actuating means'for the movable contact structure carried by grqundedxsupporting means, an insulating operating rod extending substantially longitudinally of-Lthe terminal bushing within the casingiand interconnecting the rotatable actuating :means .and the movable contact t eiiect the operation of the same. I

3. Ina circuit interrupter, supporting means at ground potential, a casing having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing extending through and being supported intermediate the ends thereof by the grounded supporting means,- the terminal bushing projecting into one end of the casing and having the interior end thereof terminating adjacent the midaportion of the casing, an arc extinguishing unit secured to the interior end of the terminal bushing, line terminal means for thein-terr-upter disposed adjacent the other end of the-casing, movable contact structure disposed within the casing and separable to establish an are within the are extinguishing unit, and an elongated operating rod of insulating material "extending substantially longitudinally of the terminal bushing in the space between the terminal bushing and the in.- sulating part of the casing for interconnecting the actuating means and the movable contact structure. i

4. In a circuit interrupter, grounded supporting means, a casing at leastthe. side wall portions of which are composed .ofinsulating material and secured to the :gmunded supporting means at one endthereof, only .a single terminal bushing for the interrupter, the terminal bushing including a conductor surrounded by insulating material and extending through the grounded supporting means, the means supporting the terminal bushing adjacent the mid-portion thereof, the terminal bushing projecting into saidone end of the casing substantially parallel to the sidewall portions thereof, the interior end of the terminal bushing terminating adjacent the mid-portion of the casing, an arc extinguishing unit secured to the interior end of the terminal bushing, line terminal means for the interrupter disposed adjacent the other end of the casing, movable contact structure disposed within the casing and including a movable contact for establishing an arc within the arc extinguishing unit, and actuating means for the movable contact structure supported by the grounded supporting means and operable to move the movable contact away from the interior end of the terminal bushing during the opening operation.

5. In a circuit interrupter, grounded supporting means, a casing at least the side wall portions of which are composed of insulating material, the casing being secured to the grounded supporting means adjacent one end thereof, only a single terminal bushing for the interrupter, the terminal bushing including a conductor surrounded by insulating material, the grounded supporting means supporting the terminal bushing adjacent the mid-portion thereof, the terminal bushing extending through the grounded supporting means and projecting into said one end of the casing substantially parallel to the side wall portions thereof, the interior end of the terminal bushing terminating adjacent the mid-portion of the casing, an arc extinguishing unit secured grounded supportin 6 to the interior and of the terminal bushing, line terminal means for the interrupter disposed ad: jacent the other end of the casing, movable contact structure including a movable contact disposed within the casing and separable to establish an are within the arc extinguishing unit, and actuating means for the movable contact structure supported by the grounded supporting means and including an elongated insulating operating rod extending substantially longitudinally of the terminal bushing interiorly of the casing and operable to move the movable contact away from the interior end of the terminal bushing during the opening operatio 6. In a circuit interrupter, grounded supporting means, a casing at least the side wall portions of which are composed of insulating material, the casing being secured to the grounded supporting means adjacent one end thereof, only a single terminal bushing for, the interrupter, the terminal bushing including a conductor surrounded by insulating material, the grounded supporting means supporting the terminal bushing adjacent the mid-portion thereof, the terminal bushing extending through the grounded supporting means and projecting into said one end of the casing substantially parallel to the side wall portions thereof, the interior end of the terminal bushing terminating adjacent the mid-portion oi the casing, an arc extinguishing unit secured to the interior end .of the terminal bushing, line terminal means for the interrupter disposed adjacent the other end of the casing, movable contact structure including a linearly movable movable contact disposed within the arc extinguishing unit, and rotatable actuating means for the movable contact structure supported by the grounded supporting means and operable to cause movement ofthe linearly movable movable contact awayfrom the interior end of the terminal bushing during the opening operation.

7. In a circuit interrupter, supporting means at ground potential, a casing-secured to said grounded supporting means and having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing extending through and being supported intermediate the a movable contact for establishing an arc within the arc extinguishing unit, the movable contact being movable into and out of the arc extinguishing unit, and actuating means for the movable contact structure supporting means and operable to move the movable contact out of the arc extinguishing unit and away from the interior end of the terminal bushing to insert an isolating gap in the circuit between the tip of the movable contact and the arc extinguishing unit.

8. In a circuit interrupter, supporting means at ground potential, a casing secured to said grounded supporting means and having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing extending through and. being supported intermediate the ends thereof by the grounded supporting means and projecting into one end of the casing, an arc extinguishing unit secured to the interior end of the terminal bushing and so disposed that a clear space exists between the arc extinguishing unit and the other end of the casing, line terminal meansdisposed adjacent said other end of the casing, movable contact structure including a movable contact for establishing an are within the arc extinguishing unit, the movable contact being. movable into and out of the arc extinguishing unit, and actuating means including an elongated insulating operating rod extending substantially longitudinally of the terminal bushing within the casing and supported by the grounded supporting means and operable to move the movable contact out of the are extinguishing unit and away from the interior end of the terminal bushing to insert an isolating gap into the circuit between the tip of the movable contact and the arc extinguishing unit. 9. In a circuit interrupter, supporting means at ground potential, a casing secured to said grounded supporting means and having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing extending through and being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing projecting into one end of the casing and having the interior end thereof terminating adjacent the mid-portion of the easing, stationary contact means associated with the interior end of the terminal bushing, line terminal means for the interrupter disposed adjacent the other end of the casing, a movable contact disposed within the casing and cooperable with the stationary contact means to establish an arc, and actuating means for the movable contact carried by the grounded supporting means.

10. In a circuit interrupter, supporting means at ground potential, a casing secured to said grounded supporting means and having a major part of the side walls thereof of insulating material, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing extending through and being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing'projecting into one end of the casing and having the interior end thereof terminating adjacent the mid-portion of the casing, stationary contact means associated with the interior end ofthe terminal bushing, line terminal means for the interrupter disposed adjacent the other end of the casing, a movable contact disposed within the casing and cooperable with the stationary contact means to establish an arc, actuating means for the movable contact carriedby the grounded supporting means and including an insulating elongated operating rod' extending substantially longitudinally of the termlnalbushing interiorly of the casing.

' LEON R. LUDWIG.

BENJAMIN P. BAKER.

REFERENCES CITED 7 Hoye Sept. 8, 1942 Baker Dec. 8, 1942 FOREIGN PATENTS Country Date Germany Mar. 22, 1923 Great Britain Nov. 19, 1935 Great Britain Aug. 17', 1939 Germany May 11, 1933 Number Number 

